Preparation of Hexagonal Boron Nitride Nanosheets by Molten Salt Nitridation Method

Hexagonal boron nitride (h-BN) nanosheets were synthesized at 900-1 200℃ by molten salt nitridation method with NaCl-KCl as molten salt medium and sodium borate and melamine as raw materials. The effects of reaction temperature, salt to reactant mass ratio and N to B molar ratio on the phase composition of the products were studied, and the micromorphology and N₂ adsorption-desorption performance of the obtained h-BN powder were characterized. The results show that the increase of the reaction temperature, salt to reactant mass ratio or N to B molar ratio favored the synthesis of h-BN phase. The h-BN nanosheets with length of 50-200 nm and thicknesses of 10-40 nm were prepared after reaction at 1 100℃ for 3 h with the salt to reactant mass ratio of 2:1 and N to B molar ratio of 2:1. The specific area of the nanosheet was 82 m²·g^-1.